From 7105319ada2e663659020cbe9fdf7ff38f421ab2 Mon Sep 17 00:00:00 2001 From: serge-sans-paille Date: Wed, 4 Dec 2019 17:02:57 +0100 Subject: [PATCH] bpo-38634: Allow non-apple build to cope with libedit (GH-16986) The readline module now detects if Python is linked to libedit at runtime on all platforms. Previously, the check was only done on macOS. If Python is used as a library by a binary linking to libedit, the linker resolves the rl_initialize symbol required by the readline module against libedit instead of libreadline, which leads to a segfault. Take advantage of the existing supporting code to have readline module being compatible with both situations. --- .../2019-12-04-15-56-28.bpo-38634.pq0ZWa.rst | 2 ++ Modules/readline.c | 23 ++++--------------- 2 files changed, 6 insertions(+), 19 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2019-12-04-15-56-28.bpo-38634.pq0ZWa.rst diff --git a/Misc/NEWS.d/next/Library/2019-12-04-15-56-28.bpo-38634.pq0ZWa.rst b/Misc/NEWS.d/next/Library/2019-12-04-15-56-28.bpo-38634.pq0ZWa.rst new file mode 100644 index 00000000000..d60c3172c2e --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-12-04-15-56-28.bpo-38634.pq0ZWa.rst @@ -0,0 +1,2 @@ +The :mod:`readline` module now detects if Python is linked to libedit at runtime +on all platforms. Previously, the check was only done on macOS. diff --git a/Modules/readline.c b/Modules/readline.c index b76861f7b04..27a993f449f 100644 --- a/Modules/readline.c +++ b/Modules/readline.c @@ -45,14 +45,14 @@ extern char **completion_matches(char *, CPFunction *); #endif #endif -#ifdef __APPLE__ /* * It is possible to link the readline module to the readline * emulation library of editline/libedit. * - * On OSX this emulation library is not 100% API compatible - * with the "real" readline and cannot be detected at compile-time, - * hence we use a runtime check to detect if we're using libedit + * This emulation library is not 100% API compatible with the "real" readline + * and cannot be detected at compile-time, + * hence we use a runtime check to detect if the Python readlinke module is + * linked to libedit. * * Currently there is one known API incompatibility: * - 'get_history' has a 1-based index with GNU readline, and a 0-based @@ -64,7 +64,6 @@ static int using_libedit_emulation = 0; static const char libedit_version_tag[] = "EditLine wrapper"; static int libedit_history_start = 0; -#endif /* __APPLE__ */ #ifdef HAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK static void @@ -693,7 +692,6 @@ get_history_item(PyObject *self, PyObject *args) if (!PyArg_ParseTuple(args, "i:get_history_item", &idx)) return NULL; -#ifdef __APPLE__ if (using_libedit_emulation) { /* Older versions of libedit's readline emulation * use 0-based indexes, while readline and newer @@ -713,7 +711,6 @@ get_history_item(PyObject *self, PyObject *args) Py_RETURN_NONE; } } -#endif /* __APPLE__ */ if ((hist_ent = history_get(idx))) return decode(hist_ent->line); else { @@ -1081,7 +1078,6 @@ setup_readline(readlinestate *mod_state) /* The name must be defined before initialization */ rl_readline_name = "python"; -#ifdef __APPLE__ /* the libedit readline emulation resets key bindings etc * when calling rl_initialize. So call it upfront */ @@ -1098,7 +1094,6 @@ setup_readline(readlinestate *mod_state) libedit_history_start = 1; } clear_history(); -#endif /* __APPLE__ */ using_history(); @@ -1127,9 +1122,7 @@ setup_readline(readlinestate *mod_state) mod_state->begidx = PyLong_FromLong(0L); mod_state->endidx = PyLong_FromLong(0L); -#ifdef __APPLE__ if (!using_libedit_emulation) -#endif { if (!isatty(STDOUT_FILENO)) { /* Issue #19884: stdout is not a terminal. Disable meta modifier @@ -1149,11 +1142,9 @@ setup_readline(readlinestate *mod_state) * XXX: A bug in the readline-2.2 library causes a memory leak * inside this function. Nothing we can do about it. */ -#ifdef __APPLE__ if (using_libedit_emulation) rl_read_init_file(NULL); else -#endif /* __APPLE__ */ rl_initialize(); RESTORE_LOCALE(saved_locale) @@ -1283,12 +1274,10 @@ call_readline(FILE *sys_stdin, FILE *sys_stdout, const char *prompt) int length = _py_get_history_length(); if (length > 0) { HIST_ENTRY *hist_ent; -#ifdef __APPLE__ if (using_libedit_emulation) { /* handle older 0-based or newer 1-based indexing */ hist_ent = history_get(length + libedit_history_start - 1); } else -#endif /* __APPLE__ */ hist_ent = history_get(length); line = hist_ent ? hist_ent->line : ""; } else @@ -1316,10 +1305,8 @@ call_readline(FILE *sys_stdin, FILE *sys_stdout, const char *prompt) PyDoc_STRVAR(doc_module, "Importing this module enables command line editing using GNU readline."); -#ifdef __APPLE__ PyDoc_STRVAR(doc_module_le, "Importing this module enables command line editing using libedit readline."); -#endif /* __APPLE__ */ static struct PyModuleDef readlinemodule = { PyModuleDef_HEAD_INIT, @@ -1340,7 +1327,6 @@ PyInit_readline(void) PyObject *m; readlinestate *mod_state; -#ifdef __APPLE__ if (strncmp(rl_library_version, libedit_version_tag, strlen(libedit_version_tag)) == 0) { using_libedit_emulation = 1; } @@ -1348,7 +1334,6 @@ PyInit_readline(void) if (using_libedit_emulation) readlinemodule.m_doc = doc_module_le; -#endif /* __APPLE__ */ m = PyModule_Create(&readlinemodule);